.container {
    width: 100%;
    height: calc(100% - 50px);

    display: flex;
    align-items: center;
    justify-content: center;
}

#screen {
    width: 450px;
    height: 50px;
    margin-top: 10px;
    background-color: rgba(255, 255, 255, 80%);
    font-size: 22px;
    line-height: 50px;
    text-align: center;
    border-radius: 50px;
}

.container button {
    width: 450px;
    height: 50px;
    margin-top: 10px;
    background-color: rgba(255, 255, 255, 80%);
    font-size: 22px;
    line-height: 50px;
    text-align: center;
    border-radius: 50px;
    border: none;
    outline: none;
}

.container button:active {
    background-color: gray;
}